Pulse train generator for producing odd or even number of pulses with variable pulse spacing



United States Patent Ofiice 3,167,716 Patented Jan. 26, 1965 Thornhiil, Accolteelr, Md, assignors to the United States of America as represented by the Secretary or j the Navy Filed Nov. 29, 1961, Ser. No. 155,370

6 Claims. (Ci. 328-38 (Granted under Title 35, US. Code (1.952 sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the pa ment of any royalties thereon or therefor.

This invention relates in genera-Ito pulse train generators and in particular to means for generating a train of a selected odd or even number of pulses.

With the advent of the data handling era, a wide variety of pulse train generators have been devised for use in computer circuitry and the like. In general, the pulse train generators in the prior art have been characterized by one or more performance compromises such as width of pulse, shape of pulse, number of pulses, stability gating requirements, etc., or by one or more circuitry cornpromises such as size, weight, durability, etc.

The permissible error tolerance in the gating means has been a particular problem in many prior art pulse train generators. In many cases, the tolerance requirement is It is an object of this invention to provide an improved pulse train generator which may be adapted to produce an odd or an even number of pulses.

It is another object of this invention to provide an improved pulse train generator which may be adapted to produce a pulse train with a multitude of different spacings between pulses.

It is still another object of this invention to provide an improved pulse train generator which allows the use of relatively inaccurate gating signals to produce a pulse train of relatively high accuracy.

Other objects of the invention will become apparent upon a more comprehensive understanding of the invention for which reference is had to the following specification and drawings wherein:

FIG. 1 is a block diagram showing of a typical prior art pulse train generator.

. FIG. 2 is a block diagram showing of one embodiment of the device of this invention.

FIG. 3 is a block diagrarn'of a second embodiment of the device of this invention.

FIG. 4 is a block diagram showing of a third embodiment of the device of this invention.

FIG. 5 is a graphical presentation of the outputs of the circuitry shown in FIGURES 1 through 4.

' opens the AND gate 14 long enough to pass the desired number of pulses through to the output.

tions, of course.- A major disadvantage, however, lies with its inherent precision gating requirement. With such'precision requirement, extreme precaution must be taken to insure the accuracy of the gate'generator output. It will be appreciated that in applications where the prior art device might be subject to significant ambient condition variations it is difiicult, if not impossible, to avoid deviations in the gate generator output. Often the precautions to be taken add greatly to the overall size and/ or weight of, the prior art and in this manner preclude its adaption to otherwise suitable applications where size and weight are critical factors.

The embodiment of the invention shown in FIG. 2 incorporates a plurality of monostable multivibrators. In this instance multivibra-tors 21 and 22 are connected to output utilization means 33 via OR gate 34. The input trigger signal is applied in this embodiment via one input of OR gate 35 to the multivibrator 21 and the output of the multivibrator 21 is connected not only to the output utilization means 33 but to an input of AND gate 36 which is connected to actuate the multivibrator 22 upon concurrent receipt of the output of monostable multivibrator 37, which is'triggered by the same input trigger signal applied to multivibrator 21. Likewise, the output of multivibrator 22 is connected not only to the output utilization means 33 but to another input of OR gate 35 via feedback means 38, such that multivibrator 21is again actuated.

Thus in the basic embodiment of FIG. 2 an odd number of pulses are generated for each trigger signal. The monostable multivibrator 37 serves as the gate generator and opens AND gate 36 such that multivibrator 21 ac-' tivates multivibrator 22 which activates multivibrator 2 1, etc., until the gate generator ceases operation, whereupon, as will be discussed hereinafter, multivibrator 21 produces the last pulse in the train and the width of the gate can vary an amount equal to twice the time between consecutive pulses.

The second embodiment of the invention, shown in FIG. 3, incorporates the same component parts as the embodiment of FIG. 2 but in such arrangement as to provide an even number of pulses in the pulse train per trigger signal. In this embodiment multivibrators 21 and 22 are connected to output utilization means 33 via OR gate 34. The input trigger signal is applied via one input of OR gate 35 to the multivibrator 21 and the output of multivibrator 21 is connected not only to the output' utilization means 33 but to the input of multivibrator 22 to actuate same. Likewise, the output of multivibrator 22 is connected not only to output utilization means 33 but to another input of OR gate 35 via feedback means 38 such that multivibrator 21 is again actuated. In this embodiment, however, AND gate 36 is interposed in the feedback means 38 and is adapted to pass the output of multivibrator 22 to multivibrator 21 upon concurrent receipt of the output of multivibrator 37 Which,'as in the. embodiment of FIG. 2, is triggered by the same input trigger signal applied to multivibrator 21.

Thus in the basic embodiment of FIG. 3, an even number of pulses, at least two, are generated for each trigger signal. Again, the monostable multivibrator 37 serves as the gate generator and opens AND gate 36 such that multivibrator 21 activates multivibrator 22 which activates multivibrator 21, etc., until the gate generator ceases operation, whereupon as will be discussed hereinafter, rnultrvibrator 22 produces the last pulse in the train and 4, isisubstantially similar to the embodiment of: 2,

but'incorporates additional multivibrators 23 and 24. In this embodiment the additional, multivibrators are activated in turn by the output of multivibrator 2.2 and the. output of the last multivibrator 24, is connected not only .to the output utilization means 33 but to another input of OR gate 15 via feedback means 38. such that muitivi: brator 21 is again actuated. Thus-it will-be appreciated that the basic'embodiment of FlG. 2 may be adapted in the manner shown in FIG. 4 to provide an output with' either an even orIan odd number of pulses and the gate Width may vary pulse'swhere it is an integer representative of the number of monostable' multivibrators involved',-exclusive of the gating generator. Further it will be appreciated that with n rnonostable rnultivibrators employed, It di.t ferent pulse spacings may be obtained. T

FIG. 5 depicts in proper time relation the output of the gatinggenerator 37, the output of each of the multivibrators'21' and 22 in the basic embodiment of FIG. 2

and the output of the deviceas produced thereby;

In FIG. 5, at time a trigger signaL in this instance anegative spike pulse, activates 'gate generator 37 and monostable -multivibr'atm 21 toproducepulses' of duration S and T respectively. Irrespective of theduration of the pulse output of gate generator 37, the pulse output;

of monostable multivibrator 21 produces an output spike pulse coincident with the trailing edge-of the pulse output of monostable multivibrator 21, at time T Assuming S is'greater than T as shown, multivibrator 22 is at time T to produce a pulse'output having a trailing edge at time T which also produces an output spike pulse coincident therewith, and activates multivibrator 21 again to produce a third output spike pulse at time T of duration T 'T Depending on the durationofthe gating pulse, S the process ccntinuesto produce-a pulse train having'a selected odd'nurnber of pulses therein; As

in the example depicted inthe drawing, with the duration,

Si, greaterthan T butless than T the device willproduce'an outputtrain of'7 pulses. I

It'will be appreciated that the duration of the pulse output'of each of the multivibra'tors maybe identical'or may diifer, as shown, and that as a consequence the device, of this invention offers greatversatility, not-only in the width of the gate but in the substantially unlimited number 'of different pulse spacings permissible. embodiment of FIG. 4, for example, the tour monostable multivibrators would afford four different pulse spacings iffdesired.

Likewise,.it will be seen that tolerance to error deviations in the duration of the gating pulse increases in pro n timesthe time between consecutive In the 9 a arms- While the several embodiments of this invention ex-' eznplarity shown in the drawingsv eachrinclude a plurality of nzonostable multivibrators, itis understood: that it is nected tosaid output-of said OR gate, means connesting the output of eachfofsaid pulse forming means inn within the purview of this invention to substitute other types of one pulse producing meanstheretor in selected applications of the device. In the higher frequency range, it would be permissible if desired, to substitute delay linecomponents up to the 10 microsec. region, for example, dependent upon size and weight limitations, it

Moreover, while the OR gate 36 and the first monostable multivibrator 21 are shown-as separate components-in the drawings, it will. be appreciated that the 'rnonostable multivibrator' might incorporate a two isoj lated inputs feature. in which case the OR 36 gate could be eliminated. 7

Finally, it is understood thatvthis invention limited only by the scope of the claims appended hereto.

' What is claimed is: p

l. Apulse train generator comprising a plurality of n monostable pulse forming meansywhere n is an integer, electrically coupled in a'ring for energizing each of said pulse forming meansin consecutive order, each of said it monostable pulse forming means having an input and an output, or GR? gate having a plurality of 12 inputs andan output, output utilization meansconto a respective input of said OR gate, an AND gate coupled in said ring ofpulse formin means, said .AND

gate having an output and at least two inputs with one input coupled to a first monostable pulseiforming means and'the output thereof coupled to another of said 1non-..

ostable pulse forming means,: gate generator means coupled to another input or" said AND g'atefor providing is tube V an output'signal of selected'duration, and trigger means coupled to said gate generator means andto one of said in said trigger means'is 'connected to thatmonostable portion to the-number of inonostable multivibrators the feedback ring. For example, considering 101 pulses in a pulse train with each pulse of the same lengthpfor simplicity, the prior art device of FIG. '1 has a requisite. gatingvpulse accuracy of i .5 percent, whereas the em-' bodiment of FIG. 2, would require a gating pulse accuracy of i 1.0 percent, the embodiment of 'FIG. 4

wouldrequire a gating-pulse accuracy of i, 2.5 percent an embodiment in accordance with the teaching of FIG. 4 but employing .6 monosta'ble multivibrators would re quire a :gating pulse accuracy of i 3.5 percent, etc.

Further, it will be seen thatthe gating pulse accuracy requirement of. the prior art device does not vary ir- 're'spectiveof the number of multivibrators involved. (To-- viously, the notable advantage of a lesser accuracy requirement becomes of increasing importance as the op crating frequency increases.

rnultivibrator whichis coupledto energize another monostable' rnultivibrator by said AND. gate.

- 6. The pulse train generator as=defined in clairn 2 wherein said first monostable multivibrator has, an OR gate inputwhicli includes at least two inputs, one inputtliereof coupled'to said triggermeans.andanother input thereof coupled to the output of said nth monostable multivibrator. g

.Ratertnees. Qite'd' by the Examiner l i UNITED STATES PATENTS ARTHUR GAUSS,Primary Examiner. 7

JOHN, J. HUCKERT, Exam iner. 

1. A PULSE TRAIN GENERATOR COMPRISING A PLURALITY OF "N" MONOSTABLE PULSE FORMING MEANS, WHERE "N" IS AN INTEGER, ELECTRICALLY COUPLED IN A RING FOR ENERGIZING EACH OF SAID PULE FORMING MEANS INCONSECUTIVE ORDER, EACH OF SAID "N" MONOSTABLE PULSE FORMING MEANS HAVING AN INPUT AND AN OUTPUT, OR "OR" GATE HAVING A PLURALITY OF "N" INPUTS AND AN OUTPUT, OUTPUT UTILIZATION MEANS CONNECTED TO SAID OUTPUT OF SAID "OR" GATE, MEANS CONNECTING THE OUTPUT OF EACH OF SAID PULSE FORMING MEANS TO A RESPECTIVE INPUT OF SAID "OR" GATE, AN "AND" GATE COUPLED IN SAID RING OF PULSE FORMING MEANS, SAID "AND" GATE HAVING AN OUTPUT AND AT LEAST TWO INPUTS WITH ONE INPUT COUPLED TO A FIRST MONOSTABLE PULSE FORMING MEANS AND THE OUTPUT THEREOF COUPLED TO ANOTHER FO SAID MONOSTABLE PULSE FORMING MEANS, GATE GENERATOR MEANS COUPLED TO ANOTHER INPUT OF SAID "AND" GATE FOR PROVIDING AN OUTPUT SIGNAL OF SELECTED DURACTION, AND TRIGGER MEANS COUPLED TO SAID GATE GENERATOR MEANS AND TO ONE OF SAID PULSE FORMING MEANS FOR CONCURRENT ENERGIZATION THEREOF. 